Collating machines for assembling a plurality of signatures into groups of collated signatures, such as books or magazines, are well known in the art. Electronic control circuitry for use in collators is also known in the art. A known collator having electronic control circuitry is disclosed in U.S. Pat. No. 3,825,246 (hereinafter referred to as the '246 patent). The '246 patent discloses a collator having a plurality of hoppers for feeding signatures in a sequence to a plurality of gathering stations in the form of pockets. The pockets move below the hoppers in a closed path. The hoppers feed a signature to the pockets as the pockets move under the hoppers.
A group of collated signatures, referred to herein as an assemblage, is formed in each of the pockets. The bottom of each of the pockets opens at a predetermined time synchronized with movement of the pockets under the hoppers. When the bottom of a pocket opens, the assemblage contained therein drops onto a delivery conveyor associated with the particular assemblage. In one embodiment disclosed in the '246 patent, the collator is divided into a plurality of sectors. Each sector has its own delivery conveyor. Thus, the number of delivery conveyors for receiving assemblages is equal to the number of sectors.
The electronic control circuitry of the collator monitors the plurality of hoppers for a misfeed to the plurality of pockets. If a misfeed occurs in one of the hoppers, then subsequent hoppers in the feed sequence are prevented from feeding to the misfed pocket. The misfed pocket continues to move in the closed path under the hoppers until the misfed pocket again moves under the hopper at which the misfeed occurred. This hopper then delivers its signature to the misfed pocket. After this pocket receives the signature, the pocket moves to subsequent hoppers to receive signatures therefrom. The result is that the misfeed condition which occurred earlier is corrected without having to stop the collator.
Although the collator disclosed in the '246 patent is able to detect and correct for an occurrence of a misfeed from a hopper without having to halt operation of the collator, the collator is unable to detect and correct for an occurrence of a fault condition downstream of one of the delivery conveyors without having to halt operation of the entire collator. If such a fault condition is detected, then the pockets are stopped so that the fault condition on the one delivery conveyor can be corrected. Since all the pockets are stopped, all delivery conveyors cease feeding and all production from the collator is stopped. This results in unnecessarily lost production from the collator sectors associated with delivery conveyors downstream of which there is no fault condition.